1. Field of the Invention
The present invention relates to an electric compression device which is applicable to a vehicular refrigeration cycle device, such as an air conditioning system.
2. Description of the Related Art
As a conventional electric compression device, Japanese Patent No. 3086819 discloses an electric compression device in which a shell (a housing) contains a compressor section and a motor section. A power semiconductor module (an inverter) for driving a motor is attached to a wall of the shell so as to face a low pressure side inside the shell.
Accordingly, a low-temperature and low-pressure refrigerant, before being compressed by the compressor section, cools the power semiconductor module. Therefore, since a dedicated radiator plate, air blower, and the like become unnecessary, it is possible to reduce costs and reduce the size of the drive circuit.
When the electric compression device is stopped, however, the refrigerant does not cool down the power semiconductor module. When the electric compression device is used under high temperature conditions such as in a vehicle engine compartment, the temperature of the operating environment increases, and the increased heat from radiation causes damage in the power semiconductor module. To ensure proper resistance to heat, it is conceivable to make the size of the power semiconductor module large, or to use a power semiconductor module having a higher resistance to heat. However, these approaches are accompanied by an increase in costs.